Currently most cargo is shipped worldwide as either low priority cargo or high priority cargo. These two categories are very distinct in terms of their shipping duration and cost. The low priority cargo is predominantly shipped using container ships and to a lesser extent using trucks and trains. Intermodal containers are used for collective handling of shipped articles stored in those containers, which allows using standard loading and unloading equipment, efficient stacking, and realizing many other cost savings. Intercontinental shipments may take weeks if not months. Even long range intracontinental shipments can take a few days and even weeks. The high priority cargo is shipped using cargo aircraft, such as jet freighters. Passenger aircraft or, more specifically, cargo area of the passenger aircraft can be also used for the high priority cargo shipments. The high priority cargo is delivered in an essentially overnight mode and mostly limited to small and light articles. Standard intermodal containers are not used because of their large size and heavy weight as well as inability of most aircraft to receive and/or transport the intermodal containers.
Huge disparities in the total shipped weight and total shipping cost exist between these two transportation modalities, i.e., the low priority cargo and the high priority cargo. The low priority cargo represents the overwhelming majority of the total shipped weight, while the high priority cargo still dominates from the total shipping cost perspective. In light of these two extremes, a great need for intermediate shipping solutions exists.
One of the main cost savings in the low priority cargo category comes from use of intermodal containers, such as 20-foot containers and 40-foot containers. These containers can be loaded at their shipping points and then transported by cargo ships, trains, and/or trucks to their final destinations without a need of handling individual articles stored in these containers. An intermodal container is handled as a single unit. The standard sizes and intermodal nature of these containers have greatly facilitated and lowered the cost of the low priority cargo. Various handling equipment has been developed, which further reduced the overall shipping costs.
However, intermodal containers have not been adopted for aircraft transportation with a few rare exceptions. As such, cost savings from use of intermodal containers have not been realized in aircraft transportation. Standard intermodal containers proved to be too large and too heavy for modern aircraft. Even the largest cargo aircraft can only fit a few 20-foot containers. Use of 40-foot containers on modern aircraft is even less feasible.
This lack of adoption comes from specific design and use of aircraft. Specifically, modern aircraft have not been designed to handle the intermodal containers. Instead, cargo aircraft are typically first designed as passenger aircraft and then adapted for cargo handling applications without major changes to fuselage, wings, and other major components of the aircraft. For example, most cargo aircraft have cylindrical fuselages suitable for high cruising speeds, high altitudes, and pressurized cabins. However, the cylindrical fuselages are not optimal for transporting intermodal containers. The standard 20-foot and 40-foot intermodal containers can only fit into such fuselage laterally and, as such, are not capable of fully occupying the available cargo space in an aircraft. Furthermore, most cargo aircraft typically lack large access ports, which complicates loading and unloading of bulky articles, such as intermodal containers. Military transport aircraft are also not generally compatible with intermodal cargo transportation system as these aircraft are designed with specific cargo in mind used in the military, such as rolling equipment (e.g., tanks and trucks), palletized cargo, or irregularly shaped cargo. Also, military aircraft are often designed with specific military missions in mind rather than with a focus on low transportation costs and ability to integrate with other civilian modes of transportation.
The inability of modern aircraft to efficiently transport a large number of intermodal containers has significantly limited expansion of aircraft transport. It should be noted that transportation not only includes carrying the intermodal containers to new locations but also loading and unloading the containers into aircraft. At the same time, new business strategies (e.g., just-in-time supply) and globalization of markets have created a strong demand for faster shipping, which often cannot be addresses by ships, trains, and/or trucks, yet demands lower costs, which cannot be realized using modern aircraft. Aircraft specifically designed to transport intermodal containers can bridge this gap and provide new transportation modality not covered by the current high and low priority options.